Declaring a variable using metadata plugin fails to resolve value for project path.

Add metadata plugin,

set Meta Data Values Type: String. Name:BR, value=scm_demo

[ X ] Expose to environment

Post Build Task - Create a TFVC label

set Label ${MD_BR}

 TFVC Project path:

works:$/BT/ITSuppt/sampleApplication/scm_demo

fails: $/BT/ITSuppt/sampleApplication/${MD_BR}

works for "Create TFVC label"

SUCCESS (Project Path = $/path/to/sampleApplication/scm_demo):
========
Querying for remote changeset at '$/path/to/sampleApplication/scm_demo' as of 'D2017-12-08T02:54:09Z'...
Query result is: Changeset #185676 by 'dev1' on '2017-10-20T23:07:36Z'.
Checking if there exists a mapping for /data/jenkins/workspace/ITSuppt/TFS_Label_Test...no.
Creating workspace 'Hudson-TFS_Label_Test-MASTER' owned by 'tfbuilder1'...
Mapping '$/path/to/sampleApplication/scm_demo' to local folder '/data/jenkins/workspace/ITSuppt/TFS_Label_Test' in workspace 'Hudson-TFS_Label_Test-MASTER'...
Created workspace 'Hudson-TFS_Label_Test-MASTER'.
Getting version 'C185676' to '/data/jenkins/workspace/ITSuppt/TFS_Label_Test'...
Finished getting version 'C185676'. Retrieved 335 resources.
Creating label 'scm_demo' on '$/path/to/sampleApplication/scm_demo' as of the current version in workspace 'Hudson-TFS_Label_Test-MASTER'...
Created label 'scm_demo'.

FAILURE (Project Path = $/path/to/sampleApplication/${MD_BR}):
========
Querying for remote changeset at '$/path/to/sampleApplication/${MD_BR}' as of 'D2017-12-08T02:53:51Z'...
FATAL: com.microsoft.tfs.core.exceptions.TECoreException: TF10122: The path '$/path/to/sampleApplication/${MD_BR}' contains a '$' at the beginning of a path component. Remove the '$' and try again.
com.microsoft.tfs.core.ws.runtime.exceptions.SOAPFault: TF10122: The path '$/path/to/sampleApplication/${MD_BR}' contains a '$' at the beginning of a path component. Remove the '$' and try again.
    at com.microsoft.tfs.core.ws.runtime.client.SOAP12Service.examineResponseDOMForFault(SOAP12Service.java:117)
    at com.microsoft.tfs.core.ws.runtime.client.SOAPService.examineBodyForFault(SOAPService.java:987)
    at com.microsoft.tfs.core.ws.runtime.client.SOAPService.executeSOAPRequestInternal(SOAPService.java:665)
    at com.microsoft.tfs.core.ws.runtime.client.SOAPService.executeSOAPRequest(SOAPService.java:444)
    at ms.tfs.versioncontrol.clientservices._03._RepositorySoap12Service.queryHistory(_RepositorySoap12Service.java:1503)
    at com.microsoft.tfs.core.clients.versioncontrol.internal.WebServiceLayer.queryHistory(WebServiceLayer.java:1573)
Caused: com.microsoft.tfs.core.exceptions.TECoreException: TF10122: The path '$/path/to/sampleApplication/${MD_BR}' contains a '$' at the beginning of a path component. Remove the '$' and try again.
    at com.microsoft.tfs.core.exceptions.mappers.TECoreExceptionMapper.map(TECoreExceptionMapper.java:92)
    at com.microsoft.tfs.core.exceptions.mappers.VersionControlExceptionMapper.map(VersionControlExceptionMapper.java:43)
    at com.microsoft.tfs.core.clients.versioncontrol.internal.WebServiceLayer.queryHistory(WebServiceLayer.java:1589)
    at com.microsoft.tfs.core.clients.versioncontrol.internal.WebServiceLayerLocalWorkspaces.queryHistory(WebServiceLayerLocalWorkspaces.java:1254)
    at com.microsoft.tfs.core.clients.versioncontrol.VersionControlClient.queryHistory(VersionControlClient.java:4264)
    at hudson.plugins.tfs.model.MockableVersionControlClient.queryHistory(MockableVersionControlClient.java:255)
    at hudson.plugins.tfs.commands.RemoteChangesetVersionCommand.call(RemoteChangesetVersionCommand.java:66)
    at hudson.plugins.tfs.commands.RemoteChangesetVersionCommand.call(RemoteChangesetVersionCommand.java:34)
    at hudson.remoting.LocalChannel.call(LocalChannel.java:45)
    at hudson.plugins.tfs.model.Server.execute(Server.java:233)
Caused: java.lang.RuntimeException
    at hudson.plugins.tfs.model.Server.execute(Server.java:237)
    at hudson.plugins.tfs.model.Project.extractChangesetNumber(Project.java:280)
    at hudson.plugins.tfs.model.Project.getRemoteChangesetVersion(Project.java:276)
    at hudson.plugins.tfs.model.Project.getRemoteChangesetVersion(Project.java:292)
    at hudson.plugins.tfs.TeamFoundationServerScm.recordWorkspaceChangesetVersion(TeamFoundationServerScm.java:394)
    at hudson.plugins.tfs.TeamFoundationServerScm.checkout(TeamFoundationServerScm.java:343)
    at hudson.scm.SCM.checkout(SCM.java:495)
    at hudson.model.AbstractProject.checkout(AbstractProject.java:1212)
    at hudson.model.AbstractBuild$AbstractBuildExecution.defaultCheckout(AbstractBuild.java:566)
    at jenkins.scm.SCMCheckoutStrategy.checkout(SCMCheckoutStrategy.java:86)
    at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:491)
    at hudson.model.Run.execute(Run.java:1737)
    at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
    at hudson.model.ResourceController.execute(ResourceController.java:97)
    at hudson.model.Executor.run(Executor.java:421)